Method of dispensing an industrial spray using both a propellant-dispersant and gas pressure

ABSTRACT

A bulk lot of silicone fluid, precharged with Freon or Genetron 11, contained in a storage drum. At the site of use a nitrogen tank and a spray nozzle are connected to fittings through the drum head.

ilmicd States Patent 51 3,640,429 Campbell Feb. 8, 1972 54] METHOD OF DISPENSING AN [56] References cm INDUSTRIAL SPRAY USING BOTH A PRoPELLANT-msPERsAN'r AND GAs UNTED STATES PATENTS PRESSURE 3,352,457 1 1/1967 Tracy et a! ..222/399 Inventor: Carl N. Campbell, Kirkwood, Mo.

Assignee: Camie Company, Inc., St. Louis, Mo.

Filed: Oct. 12, 1967 Appl. No.1 674,916

US. Cl ..222/l, 1 18/300, 239/8 Int. Cl ..B67b 7/00 Field of Search ..252/305, 314; l 18/300; 206/84;

Primary Examiner-Robert B. Reeves Assistant Examiner-David A. Scherbel Attorney-Philip B. Polster [57] ABSTRACT A bulk lot of silicone fluid, precharged with Freon or Genetron ll, contained in a storage drum. At the site of use a nitrogen tank and a spray nozzle are connected to fittings through the drum head.

4 Claims, 1 Drawing Figure METHOD OF DISPENSING AN INDUSTRIAL SPRAY USING BOTH A PROPELLANT-DISPERSANT AND GAS PRESSURE BACKGROUND OF THE INVENTION This invention relates to compositions and methods for spraying a liquid vehicle onto a surface, and in particular to industrial sprays. It has particular application to applying liquid silicone coatings to surfaces industrially, but its usefulness is not limited thereto.

Numerous liquids are now packaged in small aerosol containers which hold a mixture of the liquid vehicle and a relatively low-pressure propellant. The propellant both expels the liquid vehicle from the container and atomizes the liquid vehicle in a fine spray pattern. The use of such a container for large amounts of liquid, such s are used in industrial applications, has proven impractical.

One of the objects of this invention is to provide an industrial spray composition nd a method of applying it which will approximate the finely atomized spray pattern obtained with aerosol containers.

Another object of this invention is to provide such a method in which the liquid being sprayed can easily be maintained in a sanitary condition.

Other objects will become apparent to those skilled in the art in the light of the following description nd accompanying drawing.

SUMMARY OF THE INVENTION In accordance with this invention, generally stated, an industrial spray composition is provided in which a liquid vehicle is precharged with low-pressure propellant which serves as a dispersant. Under the prescribed conditions of use of the spray, the pressure generated by this low-pressure propellantdispersant is insufficient to move the spray composition effectively through a spray nozzle, but the propellant-dispersant does aid in atomizing the liquid vehicle when another propellant is introduced which provides the desired transporting pressure. The liquid vehicle and low-pressure propellantdispersnat are packed in a bulk container, the container is transferred to the place at which the spray is to be applied, and a source of pressurized gas is connected to the container through a coupling on a tube extending through the head of he container. An outlet spray system, consisting in the preferred embodiment of the method of this invention of a flexible hose and a standard adjustable nozzle, is connected through a coupling on a dip tube extending through the head of the con tainer nearly to the bottom of the container. In the preferred embodiment the liquid vehicle is silicone fluid, the low-pressure propellant-dispersant is trichlorfluoromethane, sold as Freon II or Genetron II, the container is a standard heavy gauge 55-ga1lon storage drum, and the high-pressure gas is nitrogen delivered from a standard tank through a pressure control valve and gauge at a gauge pressure within the range of IS to 40 p.s.i.

BRIEF DESCRIPTION OF THE DRAWING In the drawing, FIG. I is a view in perspective of one illustrative embodiment of a spray apparatus for use with the industrial spray composition and method of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing, reference numeral 1 indicates one illustrative embodiment of a spray apparatus for use with the industrial spray and method of this invention. The apparatus 1 includes a 55-gallon drum 2. Extending into the drum 2 through the head 3 of the drum 2 are a short inlet the 4 mounted through a gastight cap 5 screwed onto a standard fitting 18 on the head 3 and a long outlet tube 6 mounted through a gastight cap 7 screwed onto a standard fitting 19 on the head 3. The low end of the outlet tube 6 extends to within one-half inch of the bottom 8 of the drum 2. The up er end of the inlet tube 4 is connected by a coupling 9 to a ose IS, a

pressure gauge 11, a hose l6, and to a pressure-regulating valve 12 on a tank 10 of pressurized nitrogen. The upper end of the outlet tube 6 is connected by a coupling 12 to a flexible hose 13. On the free end of the hose I3 is mounted a spray nozzle 14, such as a Binks or DeVilbiss adjustable spray nozzle.

To assure a sanitary spray, the hoses l3, l5 and 16 are all made of clear plastic, and sanitary fittings are used throughout.

The apparatus I is used as follows in carrying out the method of this invention in applying a liquid silicone coating to a surface. At a factory, a bulk quantity of silicone fluid is charged with low-pressure propellant-dispersant. The silicone fluid may have a viscosity of 350 centistokes and the propellam-dispersant maybe trichlorofluoromethane sold as Freon l l or Genetron l l which will be referred to generally hereinafter as propellant 11. An illustrative satisfactory fill in a SS-gallon drum is 24 pounds of silicone fluid, 276 pounds propellant 11, mixed at a temperature below 24 C. The drum 2 is filled with the cool mixture of silicone and incorporated propellant l1 and the couplings 9 and 12 or the fittings l8 and 19 as shipping conditions dictate, are capped.

The drum 2 is then transported to the place at which the silicone is to be sprayed on a surface. At this location, after it is ascertained that the temperature of the contents of the drum is less than 24 C., the rest of the spraying system is assembled by installing the tubes 4 and 6, if necessary, and attaching the hoses I5 and 13 to the couplings 9 and 12. The pressure control valve is adjusted to give a desired pressure in the range between 15 and 40 p.s.i. The contents of the drum are preferably warmed to within the range of 24-35 C. The nozzle 14 is then adjusted to give the desired spray pattern, and the surface to be coated is sprayed in a conventional manner. The temperature of the contents of the drum during the spray operation should be slightly above 24 C., but preferably not over 35 C.

The method of this invention produces a finely atomized spray pattern, approximating that of an aerosol container, simply, economically, and with a minimum of danger.

Numerous variations in the method of this invention, within the scope of the appended claims, will become apparent to those skilled in the art in the light of the foregoing disclosure. Merely by way of example, the viscosity of the silicone fluid can be varied, other coating materials can be employed, other low-pressure propellants can be used, although propellant II has almost ideal characteristics, the proportions of coating material and propellant-dispersant can be varied to accommodate different viscosities of coating material and types of coating and propellant-dispersants, and other inter high-pressure gases, including compressed air, may be used as the transporting propellant. These are merely illustrative.

Having thus described the invention what is claimed and desired to be secured by Letters Patent is:

l. The method of using an industrial spray comprising connecting to a container, containing a liquid spray vehicle charged with several times its weight of low-pressure propellam-dispersant with a vapor pressure insufficient to generate the desired transporting pressure under the expected conditions of use of said spray, a source of high pressure gas having a pressure substantially higher than the vapor pressure of said propellant-dispersant and thereby forcing said spray vehicle and propellant-disperant through a spray nozzle.

2. The method of claim I wherein the liquid spray vehicle is silicone fluid.

3. The method of claim 2 wherein the high-pressure gas is delivered into said container at a gauge pressure in the range of 15 to 40 p.s.i.

4. The method of claim 2 wherein the low-pressure propellant-dispersant is trichlorfluoromethane. 

2. The method of claim 1 wherein the liquid spray vehicle is silicone fluid.
 3. The method of claim 2 wherein the high-pressure gas is delivered into said container at a gauge pressure in the range of 15 to 40 p.s.i.
 4. The method of claim 2 wherein the low-pressure propellant-dispersant is trichlorfluoromethane. 